Improvements To Tilt Cylinders On Certain 994 Wheel Loaders Caterpillar

Improvements To Tilt Cylinders On Certain 994 Wheel Loaders

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Caterpillar: Confidential Yellow

NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.

NOTE: This Program must be administered as soon as possible. When reporting the repair, use "PI3638" as the Part Number, "7751" as the Group Number, "56" as the Warranty Claim Description Code and "T " as the SIMS Description Code. Exception: If the repair is done after failure, use "PI3638" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and " Z" as the SIMS Description Code.

Completion Date

November 30, 1993

Termination Date

May 31, 1994

Problem

Improvements to tilt cylinders will provide a longer service life on certain 994 Wheel Loaders.

Affected Product
Model & Identification Number

Group I

994 (9YF6-27)

Group II

994 (9YF28-34)

Parts Needed

Dealers will need to order parts for this Program.

Group I

2 - 5P2236 Seal

16 - 3S6162 Washer

8 - 7S6369 Washer

8 - 6V5215 Bolt

2 - 9X7420 Wear Ring

4 - 1010767 Bolt

12 - 1013672 Bolt

Group II

2 - 5P2236 Seal

2 - 9X7420 Wear Ring

Action Required

See the attached procedure.

Owner Notification

U.S. and Canadian owners will receive the attached Owner Notification.

Service Claim Allowances

Group I

NOTE: This is a 36 hour job.

Group II

NOTE: This is a 32 hour job.

NOTE: U.S. and Canadian Dealers Only - This Program does not qualify for a Type 2 SIMS Report.

Parts Disposition

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

NOTE: MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE

Attach.

(1-Owner Notification)

(2 -Rework Procedure)

Copy Of Owner Notification For U.s. And Canadian Owners

Rework Procedure

Several changes have been made, at different times, to improve the tilt cylinders. The build tag on each cylinder must be checked to determine which improvements need to be made to it. The information listed on the build tag is: cylinder group number, change level (e.g., 00, 01, 02, etc.) and build date. The level of updates necessary is based on the change level. Some of the cylinders may have already been partially updated. Depending on the change level, the following needs to be done:

Cylinders With Change Levels 00 To 02

Drill and tap the 8 head bolt holes in the cylinder assembly to accommodate M36 × 4 bolts. The holes should be 72 mm deep and the threads should be 56 mm deep to accept both the 101-0767 Bolts and the 101-3672 Bolts.

Cylinders With Change Levels 00 To 03

Drill and tap 4 holes in the head for the M8 × 1.25 bolts. The holes should be 23 mm deep and be threaded at least 15 mm deep. Four 6V5215 Screws and four 7S6369 Washers will be used to hold the wiper seal in place. The holes need to be located so that the washers will overlap the wiper seal.

Cylinders With Change Levels 00 To 04

Two 101-0767 Bolts, six 101-3672 Bolts and eight 3S6162 Washers need to be used to assemble the head to the cylinder assembly. Tighten the bolts to a torque of 2750 ± 275 Nm (2035 ± 204 ft lbs). This change went into effect with 9YF28.

Cylinders With Change Levels 00 To 05

Machine the rod according to the dimensions given in Illustration 1. When assembling the rod, use a 101-9571 Piston which will be shipped directly to the dealers from Caterpillar. Tighten the nuts to a torque of 8000 ± 800 Nm (6000 ± 600 ft lbs). This change went into effect with 9YF28.

Cylinders With Change Levels 00 To 06

To prevent rod scoring, the wear band thickness in the head has been increased. Destroy all removed 8J9917 Wear Rings and replace them with the 9X7420 Wear Band when assembling the cylinder. Be sure to update all parts books with this change, as the old 8J9917 Wear Rings are serviceable in other applications. This change went into effect with 9YF34.

Cylinders With Change Levels 00 To 07

Machine a groove in the head (see Illustration 2) to accept a 5P2236 Seal as a face seal. Do not reuse the 8L9241 Seal and the 1U1770 Back-up Ring.

Illustration 3 shows what a typical cylinder will look like after all of the improvements have been made. After the cylinder has been assembled, stamp a '08' on the identification tag for future reference.

ILLUSTRATION 1